USC
About this Article
Written by: Amy Lin
Written on: June 20th, 2005
Tags: food & drink, chemical engineering
Thumbnail by: Steve Woods/SXC
About the Author
In the summer of 2005, as a junior majoring in Computer Science, Amy Lin discovered her love for frozen food while studying abroad in Paris, France. She would eventually like to petition to Picard, a French frozen food company, to expand their international market to the United States. She currently works with Microsoft in Seattle.
Also in this Issue
A Chemical Engineer's Guide to Cleaning Just About Anything Written by: Rupesh Parbhoo
Security Versus Privacy: The Engineering of X-Ray Vision Written by: Farzana Ansari
Taking Off and Landing on an Aircraft CarrierWritten by: Jeff Moring
The TrebuchetWritten by: Christopher Carrillo
Stay Connected

Volume IX Issue II > Freeze! Engineering Frozen Vegetables and Fruits
With Americans working longer hours, there is less time to create a meal from scratch. The invention of frozen food has allowed us to simply microwave a meal in a few minutes, providing us with more time to spend on our hobbies and with our loved ones. Although some people tend to stay away from frozen food due to their perceived low nutritional value, frozen vegetables and fruits are actually more nutritious than their fresh counterparts. The flash-freezing technology is responsible for trapping the vitamins immediately after the produce has ripened, which helps maintain the flavor and tenderness. The frozen food industry continues to grow and expand as more people realize its nutritious qualities and want to spend less time preparing meals.

Introduction

Arriving home famished after a hectic work day of meetings, clients and hundreds of emails, you reach inside your freezer for some quick nourishment. Frozen dinners, pizza, and vegetables rest scattered inside the cold compartment. You pick the frozen peas and lemon-herb chicken from a pile and heat it in the microwave. Ten minutes pass and ding! Dinner is served. The piping-hot chicken, surrounded by its clear juices, appears plump and succulent. The round and vibrant green peas burst with tenderness in every bite. The meal tastes and looks like you slaved many hours in the kitchen. However, it only took you a few minutes.
The time consumption and complexity of preparing meals have been eliminated since the invention of frozen food. You no longer need to spend hours to purchase ingredients, prepare the items and cook for a meal that takes few minutes to consume. All the work has been done for you by the time the food is purchased. This convenience is becoming very important with more people working longer hours at the office and wanting to spend more time with love ones outside the kitchen. The American frozen food industry has steadily increased each year and by 2006 reached $28.1 billion, a 1.8% increase from the previous year [1]. With such a revolutionary and popular product, it is important to understand the history, process, nutritional value, impact and future of frozen foods.

The Beginning of Flash Freezing

Since the process of cooking frozen food on the consumer side is simple, the complexity of creating the frozen food you buy in supermarkets is often overlooked. This process has been delicately engineered over the past decades to ensure that your meal comes out with the same nutritional qualities, flavor, and texture as if you cooked it yourself. American biologist Clarence Birdseye discovered the modern-day process of freezing food using the flash-freezing technology. While on an expedition in the Arctic, he witnessed Eskimos catching fish. These fish froze instantly in the glacier air and yet retained their full qualities of freshness upon thawing. Freezing prevented the fish from spoilage by slowing the active enzymes that would otherwise break down the flesh and produce ammonia [2]. However, this freezing process needs to be completed quickly, before the enzymes can spread all over the fish.
Clarence Birdseye/USPTO
Figure​ 1: The air-blaster freezer of Birdseye's Multiplate Quick Freeze Machine.
Using this principle of frozen fish as a basis, Birdseye realized that slowly freezing foods caused the formation of large crystals and micro-organisms, which would damage the cellular structure of the food and render it inedible. But if the food was frozen quickly, then the original cellular configuration could be preserved to lock in freshness and good taste. To accomplish this, Birdseye invented the Multiplate Quick Freeze Machine, a "double plate" freezer in the 1920s, which is shown as Fig. 1.